Enhanced antibacterial activity of ZnO-PMMA nanocomposites by selective plasma etching in atmospheric pressure

• Published in: Micro and Nano Engineering Vol. 13; p. 100098
• Main Authors: Dimitrakellis, P., Kaprou, G.D., Papavieros, G., Mastellos, D.C., Constantoudis, V., Tserepi, A., Gogolides, E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2021; Elsevier
• Subjects: Antibacterial; Antimicrobial; Atmospheric plasma etching; Nanocomposites; Nanometrology of composites; Nanotexturing; Zinc oxide; Antimicrobial; Nanotexturing; Nanocomposites; Nanometrology of composites; Atmospheric plasma etching; Zinc oxide; Antibacterial
• ISSN: 2590-0072; 2590-0072
• DOI: 10.1016/j.mne.2021.100098

We present an alternative route to enhance antibacterial activity of polymer matrix nanocomposites that incorporate biocidal nanomaterials, using open-air atmospheric pressure plasma etching. We applied He/O2 discharges to rapidly remove the upper organic layers of ZnO -PMMA nanocomposite coatings, thus increasing the surface concentration of ZnO. To quantify the ZnO concentration from SEM images on the surface of the nanocomposite material, we developed and employed a new nanometrology method based on local variances of pixel luminosities and found a rapid increase of surface fraction up to 30% for the first 2 min of plasma treatment. Plasma etching resulted in enhanced antibacterial activity against Gram-negative E. coli cells after 4 h incubation under dynamic conditions. The results revealed an almost exponential drop of bacterial concentration with ZnO surface fraction, thus confirming the direct correlation of antibacterial activity with the interfacial area of the biocidal nanomaterial. [Display omitted] •Atmospheric plasma etching applied for nanotexturing of ZnO/PMMA nanocomposite.•Surface concentration of ZnO aggregates/clusters increased with plasma etching time.•New nanometrology method developed for nanocomposite surface analysis and quantification of ZnO coverage from SEM images.•Enhanced antibacterial activity of the plasma nanotextured surfaces against E.coli was observed.•Direct correlation of antibacterial activity with the biocidal ZnO interfacial area was found.